Magnetic unit



June 20, 1939. L, WADSWORTH 2,163,161

MAGNETIC UNI T INVENTOR,

ma ATTORNEYS June 20, 1939- L. H. wADswoRTH MAGNETIC UNIT Filed May 20, 1937 2 Sheets-Sheefl 2 ATTORNEYS E 1" Patented June 20, 1939 PATENT OFFICE MAGNETIC UNH` Leslie Il. Wadsworth, New York, N. Y., assigner to Control Instrument Company, Inc., Brooklyn, N. Y., a corporation of New York Application May 20, 19.37, Serial No. 143,781

Lomme l(ci. 11s-339) This invention relates to magnetic units or motors of the type that are ordinarily used to translate variations of an electrical current into mechanical movements, or vice versa.. Examples are the actuation of a 'sound producing diaphragm, and the actuation of relay contacts, in .response to variations of an electrical current.

Generally speaking, such translating devices aren reversible in action and hence theymay be used `0 to produce variations in an electrical current, in

response to mechanicalactions such as, for example, the vibration of a diaphragm by'sound waves impinging upon it.

Many forms of translating devices have been .5 proposed for the above mentioned purposes, but difficulty has been experienced in obtaining a suiliciently powerful translating device without resorting to constructions which are undesirably large or heavy. In devices of this type, it

o is often desirable to use air gaps which are exceedingly small; and thus minute variations in the air gap (and also variations in other parts of the device) will produce a relativelylarge percentage change in operating perfomance of the device. Accordingly, great accuracy is rel quired to obtain a Amanufacturers line of magnetic units which will be uniform` in 'operating performance.

Among the general objects o! the present invention is the provision of a magnetic unit which eliminates various manufacturing and adjustment diiliculties' in connection with 'the production of a standardized line of equipment.

quate translating power and desirably small size and weight.

A further object of the invention isto produce a magnetic unit in which a desired air gap can be readily and accurately obtained Von a manufacturing basis.' -J

, A still further object of the invention is-to provide a. magnetic unit in which air gap adjustment, the location and securing of theel-mature,

The invention may be used in anylpositiom' position beingiused in the sense'rela'ting to Q' right-side-up, upside-down, etc.. Por" the sake 55 of convenience, however, the disclosurerwill be and the location and seciu'ing ofthe winding are all eifected by merely assembling the parts.

.discussed es though the device were lnthe peeition shown in Fig. 1 o1' the drawings.

Fig. 1 of the drawings is a central vertical section showing a magnetic unit of the present in vention arranged to eilfect translation to or from g a telephonic diaphragm. The view is taken in general on the'line I-I oilFlg. 2, and certain associated elements are indicated in dot-dash lines.

Fig. 2 is a .plan view of the structure shown 111.10

Fig. 1, certain associated elements being also indicated in dot-dash lines. i l y Fig. 3 is a perspective view ofthe smplex type armature used in the assembly ot Figs. 1 and 2.

Fig'. 4 is a perspective view of a shim, four of 1l which are used in the assembly oi Figs. 1 and 2.

Fig. 5 is a detail ,view and is a vertical section taken in general on the line 5 5 of Flg. 1.

Fig. 6 is an isometric view. showing one of two duplicate permanent magnet castings, or ileld o members, that are used in the assembly of Figs.

l, 2, and 5.

Fig. 'l is an isometric view of a modiiied io of magnet casting, or iield member, which may be used in an assembly such as Figs. 1, 2, and u 5, in lieu of the form of magnet casting shown in Fig. 6.

' T Fig. s is a deteil'vlew's'hewing e ferm er the invention which utilizes a duplex armature. The

view is a horizontal section taken axially through 30 the .magnetic unit in the plane of thearmature. Fig. 9 is a vertical sectional view taken in general on the line 9--3 o1' Fig. 8. Another object of the invention is to produce 35 a simplified magnetic translating unit of. ade- Fig-l0 is an isometric view showing one of the magnet castings, or eld members, used in Figs. g5 8 and 9. A Reference will Afirst be had to Figs. 1 to 6 inelusive. A telephonie diaphragm Ii of known construction Vispositioned in an annular base i2 .through a centrally located hole iifin the base i2. Attached to the base i! is asuitablecover l1, whichencloses the magnetic unit 20. Within the cover there maxe be' othervelements suchl as a condenser il.

Referring to Fig. 6, there is shown a one-*piece magnet casting, or -ileld member, designated as a whole by 2|. This casting has a base portion 22 from one end of which a low boss 2l projects VAfupwardly, and from the otherend ot which a pelel pieee u prejeets upwardly. At ne sides, the u vertical grooves 21, 21. This casting is made of known permanent magnet material, which when magnetized, gives a magnet of very high flux density. Various specific alloys containing nickel, aluminum, and steel are known for this purpose. The casting is magnetized by known procedure,

and various arrangements of polarities may beV utilized. For the magnetic unit disclosed, I prefer to make both of the side walls either north or south poles, with the pole piece 24 either north or south. In thus magnetizing the eld members, they are magnetized in pairs of opposite polarities; and the pairs are so assembled that north poles face south poles, both as to poles 24 and as to side walls 25 and 26. The top of pole pie'ce 24 and the tops of side Walls 25 and 26 are all preferably ground accurately to be flat surfaces lying in' a single plane.

Fig. 3 shows a sheet metal stamping 30 of magnetic material which is used as an armature in the assembly of Figs. l, 2, and 5. This. stamping has supporting legs 3|, 3| which are arranged to register'with the top surfaces of magnet side walls 25 and 26. It also has an armature leg 32 which can vibrate as a reed; and the leg 32 is pierced at 33 to receive diaphragm connector |6. Stamping 3U is preferably made of magnetic material which is low in residual magnetism. In the particular device illustrated in .the drawings this armature stamping is relatively thin; and in some instances its thickness has been #.0175 inch in actual practice. A material of which the armature stamping has been made is 4% silicon steel. Fig. 4 shows a shim 35 V4of' magnetic material f having a shape corresponding to the top surface of magnet walls 25 and 26. The thickness of this e shim depends upon the thickness of air gap desired in the assembly, assuming that the top of pole 24 is so ground as to lie in the same plane as vthe tops of walls 25 and 26.

A permanently magnetized field member such as shown in Fig. 6 is placed directly against the base I2.' Qn top of each of the walls 25 and 26 aA shim 35 such as shown in Fig. 4 is so positioned as' to register with the top surface of the wall. An -energizing coil 36 is telescoped over armature leg 32, and then the armature' stamping is positioned'on top of the shims with the legs 3| 3| also in registration with the tops -of walls 25 and 26. Then another pair of shims is placed on top of the legs 3|, 3| in registration. therewith. Another magnet casting, or,eld member, 2| such' as shown in Fig. 6 is then inverted and placed 'on top of the uppermost'shims with the surfaces of the walls 25 and 26 in kregistration-with the shims" and legs 3| 3|. A vretainer piece 42 is placed onposition. In Figs. 14 and5 the coil is shown as a winding 31 on a spool of insulating material. The spool has a hollow core 38 which is spaced from armature-leg 32, and has ends 39, 39. The ends 39, 39 are suciently yielding to be appropriately clamped bythe contact of-the magnet casting, despite manufacturing variations in size.

The ends of the magnet castings 2|, 2| 'are recessed at 28 (Figs. 1 and 2) to permit diaphragm connector I6 to be placed close to poles 24,24 while arranging for a very high flux density field between these poles. The retainer 42 may be formed with a depending flange 4|, on which is mounted a terminal bar 40.

. In the assembly, the facing top surfaces of walls 25 and 26 are of opposite polarity whereby the parts are magnetically drawn together. This tends to eliminate any undesired air gaps in the assembly and provides conditions favorable to full retention of field magnetism at the highest value.` The facing-poles 24, 24 of the assembly are of opposite polarity so that the vibratory end of armature leg 32 lies in a-strong magnetic eld. The air gap between the armature leg and each of the pole pieces 24 is accurately established by shims 35 and no adjustments are required. Nonmagnetic material is preferably used for all parts except magnet castings 2|,4armature stamping l 36, and shims 35.

. Conversely, mechanical vibration of diaphragm l I may be used to produce current variations in a circuit containing the winding of coil 36.

The form of magnet casting, or field member,

45 shown in Fig. '1 differs from that of Fig. 6 only by the addition of another pole piece 46. The

top of pole piece 46 is accurately ground to lie in the same plane as the top of pole piece 24, and is preferably magnetized to opposite polarity. When two field members such as 45 are substituted into the assembly ofjigs. l, 2, and 5, the armature leg 32 is fpositioned between two pairs of pole pieces, since an additional pair is provided by poles 46. This increases the sensitiveness of the magnetic unit, though lesser armature-,actuating efect is obtained at pole pieces 46, due to the shorter lever arm at which they influence armature leg 32.

The form of the invention shown in Figs.l 8,'9, and 10 utilizes a duplex type armature 50 having two armature tongues 5| and 52. As shown, the diaphragm connection |6 is made to tongue 5|. Two one-piece magnet castings, or `field members, of the form shown in Fig. 10 are used in the assembly. These have a bottom portion 56 from which project upwardly a boss 5 1 and pole pieces 58 and 59. Side-wall portions 66 and 6| are alsovprovided; and the tops of the side walls and of poles 58 and 59 are all preferably so ground as to be atand lie in a single plane. In magnetizing, the walls 60 and 6| are made of such polarities that inthe assembly each of these poles faces. one of opposite. polarity. Poles 58 and 59 g may be of either north or south polarity; and in one-casting they may be of the same or opposite polarity. However, in the assembly each of these poles faces one of opposite polarity.

vTwo windings 63, 63 are used, one surrounding armature tongue 5|, and the other surrounding armature tongue 52. As against axial movement, the windings are held by the opposing vertical faces of boss l51 and poles 58 and 59, respectively. The windings .are also gripped radially by' the clamping together of thetwo magnet castings, which iseected after the manner shown in the first form ofthe invention. 'I'he windings 63 are shown as of the self-supporting type, and they amarsi 3 may be surfaced inside and out with insulating material as shown. Appropriate shims are used to establish the air gap; and as to details not referred to, the structure is similar to the first form of the invention.

In operation, the two coils 63 are connected to the same circuit (preferably in series); and the connections are such that tongue 5l is influenced downwardly when tongue 52 is influenced upwardly, and vice versa. Thus, the diaphragm rereceives the actuating force of each armature tongue.

While a spool type winding has been shown in Fig. 1 and a self-supporting type winding in Fig. 8, it will beA understood that either form of winding lmay be used in any of the forms of the invention.

In compliance with the patent statutes, I have shown the best forms in which I have contemplated applying my invention, but it will be understood that the forms disclosed are illustrative and not limiting.

What is claimed is:

1. A magnetic unit comprising: a pair of complementary one-piece permanent magnet field members, each field member being composed wholly of magnetic material land having spaced sidewall portions and an integral salient pole positioned between said side walls, and each of the iield members having the tops of its side walls and the top of its salient pole all lying permanently in a single plane; a sheet metal armature member positioned between the field members; shims of magnetic material between the armature member and the iield members; and means to securev the field members together.

2. A magnetic unit comprising: apair of complementary field members, each being formed in one-piece of permanent magnet material and each including Aa body portion from one side of which project at least one salient lpole and a pair of separate side walls spaced apart and located on opposite sides of the pole, the tops of said pole and side walls being all accurately and permanently located in a single plane, the field members being permanently magnetized with the salrent poles and side walls as magnetic poles, and the two held members constituting the sole field excitation of the unit and being assembled with the tops of their side walls and the salient poles 1n opposed face-to-face relationship, respectively, and the field members being arranged with a side wall of north polarity facing one of south polarity and with a salient pole of north polarity 5 facing one of south polarity; a nat sheetmetal armature of magnetic material having supporting portions positioned between the opposed tops of the side walls of the field members, and having a vibratile tongue positioned bet'ween the opposed salient poles; lan amature energizing coll surrounding saidtongue and positioned between the body'portions of the field members; shims of magnetic material on each side of each of the armature supporting portions, said shims establishing the spacing `between said vibratile tongue and the salie'nt poles; and means to mechanically urge the neld members toward each' other and thereby clamp said armature, shims, andcoilbetweensaidfieldmembers,theiield members GDM!!! Nid uhmm the coil independentlyoftheclampingofthearmature.

3. A magnetic unit comprising: a pair of complementary eld members, each being formed in one-piece of permanent magnet material and each including a body portion from one side of the salient poles and wall portions as magnetic poles, and the two field members constituting the sole eld excitation of the unit and being assembled with the tops of their wall portions and the salient poles in opposed face-to-face relationship, respectively, and the field members being arranged with a wall portion of north polarity facing one of south polarity and with a salient pole of north polarity facing one of south polarity; a flat sheet metal armature of magnetic material having at least one supportingzo portion positioned between the opposed tops of the wall portions of the field members, and having a vibratile tongue positioned between the opposed salient poles; an armature energizing coil surrounding said tongue and positioned between the body portions of the field members; shims of magnetic material on each side of the armature supporting portion, said shims establishing the spacing between -said vibratile tongue and the salient poles; and means to mechanically urge the field members toward each other and thereby clamp said armature and shims between said field members. 4. A magnetic unit comprising: a pair of complementary field members, each being formed in one-piece of permanent magnet material and each including a body portion from one side-of which project two spaced salient poles and a pair of spaced side walls located laterally on opposite sides of the poles, the tops of said poles and two eld members constituting the sole field exa citation of the unit and being assembled with the tops of their side walls and with the salient poles in opposed face-to-face relationship, respectively, and the field members being arranged with each side wall of north polarity facing one of o south polarity and with each salient pole of north polarity facing one of south polarity; a at sheet metal armature of magnetic material having supporting portions positioned between the opposed tops of the side walls of the field members, and u having vibratile tongues positioned respectively between the opposed pairs of salient poles; a pair of armature energizing coils, one surround` ing each vibratile tongue, and the coils being positioned between the body portions of the held l -members; shims of magnetic material on each side of each of the amature supporting portions, said shims establishing the spacing between said vibratile tongues and the salient poles;

and means to mechanically urge the field u" I bers toward each other and thereby clamp said armature, shims, and coils between said field members. the field members ensuing and clamp- I ing the coils independently of the clamping of the armature. y

LFSLB B. WADSWORTH. 

